Working fluid for compression refrigeration systems



Patented Sept. 26, 1950 WORKING FLUID FOR COMPRESSION REFRIGERATIONSYSTEMS Stanley V. Cook, Dayton, and Alfred E. Bishop, Oakwood, Ohio,assignor to General Motors Corporation, Dayton, Ohio, a corporation ofDelaware No Drawing. Application September 21, 1946, Serial No. 698,423

'7 Claims.

This invention relates to chemistry and more particularly to a workingfluid for use in refrigerating systems.

In refrigerating systems employing a halogenated hydrocarbon as therefrigerant, slight traces of corrosion and copper plating have beendiscovered. It is believed this corrosion is due to slight traces ofsuch end products as water and hydrochloric acid probably formed by theslow break-down of the refrigerant at temperatures occurring on the hightemperature side of the system. The presence of water, is alsoobjectionable in that it may result in the formation of ice crystals onthe cold or low pressure side of the system.

To overcome this latter objection it has been the custom to add to thelubricant and the refrigerant a small amount of an antifreeze such asmethyl alcohol. It has been found, however, that the addition of suchantifreeze increases the corrosive and copper plating action takingplace within the system.

It is the object of our invention to provide a Working fluid whichincludes in addition to the halogenated hydrocarbon refrigerant andlubricant either with or without the antifreeze, one or more organicoxides of the type in which the oxygen atom is directly linked to twononadjacent carbon atoms.

As one specific example of our invention, we employ as a refrigerantdifiuorodichloro methane. As a lubricant, we employ mineral oil. Theamount of refrigerant and the amount of the mineral oil varies with theparticular refrigerating system in which the working fluid is to beused. For example, the amount of lubricant required will vary accordingto the amount of lubricant space provided in the compressor as well asto the efiiciency of the separation of the lubricant from therefrigerant after compression and to the dependability and effectivenessof the return of the lubricant from the other parts of the system to thecompressor. In general, the amount of lubricant will vary betweenone-fifth and an amount equal to the refrigerant by weight, dependingupon the characteristics of the system wherein it is to be used. Whereno alcohol is to be used in the system, we include propylene oxide 1,3in the amount o /,g% to 5% of the refrigerant.

Where alcohol is to be used, we prefer to use methyl alcohol. In thisevent, the alcohol may be in the proportion of. nine times the amount ofthe propylene oxide 1,3 but a greater pro- 7 portion of propylene oxidesuch as in the proportion of 2 to 3 may be used if desired. Wherealcohol is used we prefer to limit the combined total of the propyleneoxide and the alcohol to between and 5% of the amount of the refrigerantin the system.

Instead of the particular fluorine refrigerant named above,tetrafiuorodichloroethane, methyl, methylene or ethyl chloride, or oneof the other refrigerants mentioned in the Midgeley et al. ReissuePatent 19,265, may be used. The mineral oil should be as free fromcorrosive substances as possible and of the proper viscositycharacteristics. Synthetic lubricants may be used in place of themineral oil.

Instead of the propylene oxide 1,3, the inhibitor may be selected fromother members of the same series, which includes butylene. oxide 1,3,butylene oxide 1,4, pentylene oxide 1,3, pentylene oxide 1,4, pentyleneoxide 1,5, pentylene oxide 2,4, hexylene oxide 1,3, hexylene oxide 1,4,

hexylene 1,5, hexylene oxide 1,6, hexylene oxide. 7

tem, such as methyl alcohol, ethyl alcohol, normal propyl'and isopropylalcohol, normal butyl and isobutyl alcohol, tertiary butyl alcoholandbenzyl alcohol. The lower alcohols appear to be more effective asantifreezes, but the higher alcohols appear to contribute lesscorrosion. However, in all cases it appears that by the use of one ofthe members of the oxide series above described, particularl thepropylene oxide 1,3,

corrosion is efiectively retarded and prevented.

The working fluids above described inhibit thes corrosion and copperplating action within the refrigerating system. This may be due to thefact that the organic oxides above described act to stabilize therefrigerant.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, as may come within the scope of the claims whichfollow.

What is claimed is as follows:

1. A working fluid for a compression refrigerating system consisting ofas its major constituents a refrigerant halofluoro derivative of analiphatic hydrocarbon as the refrigerant and mineral oil and as itsminor constituent a mono-hydroxy alcohol having no more than 4 carbonatoms in the molecule and an organic oxide inhibitor of the type inwhich the oxygen atom is linked directly to two non-adjacent carbonatoms in a linked hydrocarbon chain of 3 to 6 carbon atoms, saidinhibitor bein in an amount not more than of the refrigerant in thesystem.

2. A working fluid for a compression refrigerating system which consistsof as its major constituents a refrigerant fluorochloro derivative of analiphatic hydrocarbon and a mineral oil lubricant and has as a minorconstituent propylene oxide 1,3 in an amount of not more than 5% of therefrigerant in the system.

3. A working fluid for a compression refrigerating system which consistsof as its major constituents a refrigerant fluorochloro derivative of analiphatic hydrocarbon and a mineral oil lubricant and has as a minorconstituent propylene oxide 1,3 in an amount of not more than 5% of therefrigerant in the system and a mono-hydroxy alcohol having no more than4 carbon atoms in the molecule.

4. A Working fluid for a compression refrigerating system which consistsof as its major constituents a halogenated aliphatic hydrocarbonrefrigerant and a liquid mineral oil lubricant and has as a minorconstituent no more than an amount equivalent to 5% of the refrigerantof a member selected from the group consisting of propylene oxide 1,3,butylene oxide 1,3, butylene oxide 1,4, pentylene oxide 1,3, pentyleneoxide 1,4, pentylene oxide 2,4, pentylene oxide 1,5, hexylene oxide 1,3,hexylene oxide 1,4, hexylene oxide 1,5, hexylene oxide 2,4, hexyleneoxide 2,5, and hexylene oxide 1,6.

5. A working fluid for a compression refrigerating system which consistsof as its major constituents a halogenated aliphatic hydrocarbonrefrigerant and a liquid mineral oil lubricant and has as a minorconstituent no more than an amount equivalent to 5% of the refrigerantof a member selected from the group consisting of propylene oxide 1,3,butylene oxide 1,3, butylene oxide 1,4, pentylene oxide 1,3, pentyleneoxide 1,4, pentylene oxide 2,4, pentylene oxide 1,5, hexylene oxide 1,3,hexylene oxide 1,4, hexylene oxide 1,5, hexylene oxide 2,4, hexyleneoxide 2,5 and hexylene oxide 1,6, and a mono-hydroxy alcohol having nomore than 4 carbon atoms in the molecule.

6. A working fluid for a compression refrigerating system consisting ofas its major constituents a halogenated hydrocarbon refrigerant and aliquid mineral oil lubricant, and as its minor constituent an organicoxide inhibitor of the type in which the oxygen atom is linked directlyto two non-adjacent carbon atoms in a linked hydrocarbon chain of 3 to 6carbon atoms, said inhibitor being in an amount not more than 5% of therefrigerant in the system.

'7. A working fluid for a compression refrigerating, machine consistingof as its major constituents a halogenated hydrocarbon refrigerant and aliquid mineral oil lubricant, and as its. minor constituent amono-hydroxy alcohol having no more than 4 carbon atoms in the moleculeand an organic oxide inhibitor of the type in which the oxygen atom islinked directly to two non.- adjacent carbon atoms in a linkedhydrocarbon chain of 3 to 6 carbon atoms, said inhibitor being in anamount not more than 5% of the refrigerant in the system.

STANLEY V. COOK. ALFRED E. BISHOP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,040,905 Zellhoefer May 19, 19362,149,947 Zellhoefer Mar. 7, 1939 2,185,332 Crampton Jan. 2, 1940 OTHERREFERENCES Gregory: Uses and Applications of Chemicals and RelatedMaterials, vol. II, page 2'77, Reinhold Publishing Corp., N. Y. C.,(1944)

1. A WORKING FLUID FOR A COMPRESSION REFRIGERATING SYSTEM CONSISTING OFAS ITS MAJOR-CONSTITUTENTS A REFRIGERANT HALOFLUORO DERIVATIVE OF ANALIPHATIC HYDROCARBON AS THE REFRIGERANT AND MINERAL OIL AND AS ITSMINOR CONSTITUENT A MONO-HYDROXY ALCOHOL HAVING NO MORE THAN 4 CARBONATOMS IN THE MOLECULE AND AN ORGANIC OXIDE INHIBITOR OF THE TYPE INWHICH THE OXYGEN ATOM IS LINKED DIRECTLY TO TWO NON-ADJACENT CARBONATOMS IN A LINKED HYDROCARBON CHAIN OF 3 TO 6 CARBON ATOMS, SAIDINHIBITOR BEING IN AN AMOUNT NOT MORE THAN 5% OF THE REFRIGERATOR IN THESYSTEM.